Why can't the DB write the file?

Question

PostgreSQL

Project Back logs give such an error when trying to write data to the database.
Enough disk space ( 2.5G 6.9G 27% /var)
{"message":"Error getting statistics --- error: could not write to file \"base/pgsql_tmp/pgsql_tmp3261624.0\": No space left on device!","date":"2021-12-13T15:22:17.470Z","level":"error","service":"work_node"}

The code in sending logs has not changed. Processes stopped and started again, rebooted. With what this error can be connected?

Answer 1

With the fact that the disk space is over. Didn't have the strength to translate "No space left on device"?